These two tasks can sometimes be far removed from one another. So how does one find the balance when, inevitably, there will be students who want to go to college in some "work field" classes and there will be some people who prefer to go straight into the field in some "collegiate engineering" classes. It's a question of not only teaching implications, but of moral implications as well.
I think that the solution lies in approaching every problem from two perspectives at the same time. Here at BYU I had a math professor who always labeled his lectures with two parts, the "mechanic's point of view" and "the engineer's point of view". The first point of view was an expository on what knowledge would be required if you merely needed to fix a part; the latter being a point of view exposing the knowledge that would be required if you needed to design the part. This juxtaposition always left me wanting to be more like the engineer, but allowed me to feel capable, like the mechanic. I think this is a viable strategy in tech classes.
I think that using the mechanic vs. engineer point of view helps us both prepare students for the workforce while also pointing students to the virtues of higher education.